One of the most common forms of material handling equipment is an auger flight conveyor. In an auger flight conveyor a spiral member is customarally interconnected with a centrally located mounting tube which is mounted for rotation within a trough or a cylindrical tube. The inner edge of the auger flighting may either be disposed immediately adjacent the surface of the mounting tube or be spaced away from the surface of the mounting tube, and if the inner edge of the flighting is spaced away from the mounting tube it is generally referred to as a ribbon flight conveyor. In the prior art the flighting, whether ribbon flight or flighting which has the inner edge disposed immediately adjacent the mounting tube, has been formed of either sheet metal, or in ribbon flight conveyors of spiral rods. If the flighting is made of sheet metal it can be formed by running sheet metal through a flight forming machine which distorts the sheet metal from a generally elongated rectangular shape into a spiral shape. Alternatively, the sheet metal flighting may be formed by cutting out sheet metal discs, forming a radial cut in the discs, and pulling the adjacent edges away from each other to the desired pitch and then mounting the discs upon the mounting shaft. In the first of these situations expensive machinery is required and many manufacturers o machinery which utilize auger conveyors do not have a sufficient conveyor volume to justify the cost of such machinery and therefore are compelled to order augur flighting from specialty manufacturers, such orders frequently not being filled for long periods of time.
Ribbon flighting formed of single spiral rod, such as the type shown in U.S. Pat. No. 2,742,139 issued Apr. 17, 1956 to M.L. Smallegan, also generally require a special machine for forming the rod into a spiral shape. Again, many small manufacturers cannot justify the cost of such machinery and are required to purchase the flighting from specialty manufacturers.
In the past it has been proposed to make ribbon flighting from a plurality of rod-like elements which are interconnected to each other, one such example being shown in U.S. Pat. No. 1,515,552 issued Nov. 11, 1924 to E. Cravens. Such a design, however, also requires machinery to form the rods into segments of a spiral and it is not practical to advantageously utilize the principles shown in this patent for forming ribbon flight conveyors of differing pitches and diameters.